Windows 8 Success Hinges on $10 Component

By

Ben Worthen

Oct. 26, 2012 3:47 p.m. ET

The success of
Microsoft
Corp.'s
new operating system may hinge…on hinges.

Hardware companies are grappling with the fact that the Windows 8 software has a touch-oriented user interface. That means not simply adding touch screens to computers but redesigning the hinges that connect screens and keyboards to withstand new twisting, turning and poking.

Computer makers have teams of engineers designing joints, pivots and connectors for machines running the new software. They measure torque, test different springs and gears, and open and shut devices thousands of times.

The software is also inspiring designers to dream up devices that convert from a clamshell mode to function like a tablet.

"The hinge is the key to making it work," says Jeff Barney, vice president of
Toshiba
Corp.'s
U.S. PC group. A bad hinge, he added, "is the Achilles' heel of a laptop."

Customers, for example, aren't going to be happy if the angle of their new notebook or desktop computer display keeps shifting after they've touched it to open a file or surf to a website. But the hinge still must be supple enough to open and close easily.

ENLARGE

The new Surface
Associated Press

More on Windows 8

Microsoft launched its new Surface tablet on Friday, competing with Apple's iPad and a host of tablets using Google's Android operating system. The Surface represents Microsoft's latest volley in the battle for consumers' wallets, from the software company that has controlled desktops for a generation.

All this concern for components that contribute less than $10 to the cost of a computer. Microprocessor chips, displays and the operating system can all cost closer to $100.

Yet bringing touch from tablets to PCs is a high-stakes topic. Microsoft and its hardware allies, facing slowing sales, are desperate to adapt to habits from the mobile world that have made keyboards and computer mice seem old hat.

So engineers that specialize in hinges have gone back to the drawing board, testing new concepts and taking new measurements.

On a new desktop, for instance, Dell determined that the screen is best touched at angles between minus five degrees and 60 degrees, Mr. Musgrave says. That is partly based on the distance someone would need to reach the top of the screen from a seated position even though he expects that many people will choose to touch the computer while standing.

The hinge needs to let someone rotate the screen without much effort, but not give when someone touches it. Mr. Musgrave says that Dell's formula includes ball bearings and springs. There are other "tensioning forces" too, he says, which combine to create what hinge insiders call "sticktion."

There are some widely-known rules for hinges. For instance, never put steel and aluminum in the same hinge as it will corrode. Zinc, on the other hand, is considered a go-to metal for laptop hinges because it is robust and shapeable.

Some PC companies pride themselves on their ability to design hinges. Toshiba, for instance, has six engineers in Japan who just work on hinge design, and the company has been awarded more than 50 hinge-related patents.

The company's flagship Windows 8 device is a tablet with a screen that slides and pivots to reveal a laptop. The goal was to obscure the keyboard when the machine is in tablet mode and avoid designs that required twisting the screen.

The initial hinge had a sliding mechanism on each edge of the back of the screen. It was "unsellable with this hinge," says Mr. Barney. If a person pressed down on one side harder than the other, the screen would shift off-center.

A week later, the designers came up with a solution: miniature gears made of firm plastic that even out the pressure. They later added a small metal bar supported by a spring to further balance the hinge. Now the screen slides evenly even when the closing push is off-center.

The downside: "It looks a little prototypish in back," says Mr. Barney. But the hinge is hidden when the device is in tablet mode and people tend not to look at the back of their computers much.

Lenovo Group
Ltd.
, in order to make sure the 360-degree hinge it designed for its new Yoga convertible PC was up to the challenge, created a machine that opened and closed the computers 25,000 times. The company also made sure it didn't make any creaking sounds, says Andreas Schupp, strategy director for Lenovo's industrial design center.

A design team at
Hewlett-Packard
Co.
spent three months trying to perfect the hinge on a new laptop with a detachable screen. The company finally settled on one that used magnets to guide the screen into its dock, an experience that Stacy Wolff, vice president of design at H-P compares with the door on a luxury car.

In order to make a laptop easy to open and close, hinges are designed to have very little resistance between zero and five degrees, when someone first opens or finishes closing it. The torque spikes around 10 degrees and then levels off, staying the same through the rest of the screen's range of motion.

That doesn't work for a touch screen, says Sumit Agnihotry, vice president of product marketing at
Acer
Inc.
Because people were likely to push on the screen at past-upright positions, it needed more resistance. So engineers at the Taiwan-based computer maker came up with a "variable torque hinge" that increases the amount of resistance beginning at 100 degrees.

Acer borrowed an idea from architecture. A traditional hinge that was attached by screws to the bottom of the screen might warp over time if subject to constant touching, the company concluded. So instead it made the entire screen part of the hinge, like the T-beams used in buildings, to increase the stiffness.

"After a few designs we realized that the unibody design was imperative," Mr. Agnihotry says. "You need a hinge that's stronger than today's notebook."

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